R/O Critical?

This is a discussion on R/O Critical? within the Beginner Saltwater Aquariums forums, part of the Saltwater Fish and Coral Reef Tanks category; -->
I'm researching starting a 28 Gal SW, and have read that R/O water is critical, but have also read that treating with stuff like ...

I'm researching starting a 28 Gal SW, and have read that R/O water is critical, but have also read that treating with stuff like Amquel is sufficient. My water supply is from a very clean aquifer, I don't even condition it for my FW, there is very little if any as far as chlorine/chloramines in it. Just wondering if R/O is an absolute must or if it can be done otherwise. Thanks!

I know people who have used tapwater for their SW tanks, and have spoken to many reefkeepers who get their water from the tap. You may need to battle pest algae/contaminants more often, but it can be done.

R/O water is the best option though, obviously. I'd recommend doing everything in your power to obtain it, I have had very few issues with my water only using R/O.

I second MattD... aside from Chlorine and the like, if you want to test your local water supply for stuff that will feed algae (the main problem with using tap water for saltwater tanks), then check the level of phosphates (and silicates? anyone?) in the tap water. Thats the stuff that will lead to unsightly algae explosions, and it can't be removed by adding chemical treatment to the water (as far as I know). R/O water is free of phosphates and silicates, whereas my local tap water (Gainesville, FL) is loaded with phosphates.

If you are really wanting to use tap water, and you find out that your local water supply is fairly clean, then you might be able to get by by using a phosphate sponge in your filter to help keep the phosphates in check. But thats just an idea, like MattD said the best way is to just use R/O.

If you can get the R/O unit. I work in a fish store and I talk to a lot of people running saltwater tanks. From what I have noticed those who use tap water are also more likely to have nasty outbreaks of cyanobacteria. It can still happen with R/O but the cause is easier to diagnose. As in any case with the fish world there is never a 100% sure answer but there is definitely a higher percentage of tap water users getting cyanobacteria for what would appear to be no reason.

i use tap water for my 10gal SW and i use a phosphate sponge in my filter and seems to be doing very good at the moment......my tank had an outbreak before due to the high levels of phosphate in my tank so i got phosphate sponge and haven't seen any purple algae on my sand since.....It really your decision